高導熱相變化複合材料之製備

Preparation of phase change material/highly conductive filler composites

林育瑛(Yu-Ying Lin)

指導教授 ： 石燕鳳博士

朝陽科技大學/理工學院/民生化工產業研發碩士專班/碩士(2012年)

摘要

本研究目標在研製高導熱石蠟相變化複合材料，以石蠟(paraffin wax)為基材，導入經由酸化與十八烷醇改質處理之膨脹石墨(expandable graphite)及多壁奈米碳管(multi-walled carbon nanotube)作為導熱添加劑，再將絕緣無機填充料氮化硼(BN)加入，經由分散技術，使得石蠟與無機添加物間之相容性提升，成為具相變化功能之導熱複合材料，並對於複合材料之熱傳導、熱性質、型態學及電氣性質進行探討。
由熱傳導可得知當有機改質無機填充料添加到石蠟後，熱導係數由0.2566提升到4.402 W/mK，顯示傳導的路徑及網路形成，有助複合材料的散熱行為；由掃描式電子顯微鏡(SEM)觀察複合材料的表面形態，顯示經有機改質之無機填充料與石蠟之分散性、相容性有所提升；由微差式掃描熱分析(DSC)，複合材料的相變溫度與石蠟相似，其相變潛熱與複合材料中石蠟含量成正比；由儲熱/放熱性能測試結果發現，複合材料其儲熱時間比石蠟減少73.7%，放熱時間比石蠟減少90.1%，且在固-液相變時不會有石蠟滲出；表面電阻會隨著導熱填料的加入而降低，最低為7.26×100 Ω/cm2，由以上結果顯示，添加改質導熱填料可改善複合材料的導熱性能，且能降低表面電阻。

關鍵字

膨脹石墨 ； 石蠟 ； 氮化硼 ； 多壁奈米碳管 ； 熱傳導

並列摘要

As a phase change material (PCM), paraffin has high latent heat, but low thermal conductivity. In this study, expanded graphite (EG), multi-walled carbon nanotube (MWCNT) and boron nitride (BN) were added into paraffin to form a high thermal conductivity composite material with high latent heat value. Moreover, the EG, MWCNT and boron nitride were organo-modified to improve the compatibility with paraffin. Thermal conductivity of paraffin (0.2566 W/mK) was increased to 4.402 W/mK by adding of the modified fillers. The results of scanning electron microscope show that the dispersion and compatibility between inorganic fillers and paraffin were improved by the organic modification of fillers. Moreover, differential scanning thermal (DSC) analysis reveals that the phase change temperature of PCM are similar to that of paraffin, and the latent heat of PCM is based on the mass fraction of paraffin in the PCM. The results of heat storage and release tests indicate that the time of thermal-energy storage and release of the PCM was decreased by 73.7% and 90.1%, respectively as compared with that of paraffin. Moreover, there was no exudation of paraffin liquid during the solid-liquid phase change process. The surface resistivity is decreased by adding the hybrids filler, the minimum value is 7.26×100 Ω/cm2. On the basis of all results, it revealed that the use of modified filler hybrids can be considered an effective method to improve the thermal conductivity of paraffin also reduce the surface resistivity of PCM.

並列關鍵字

Paraffin ； Expandable graphite ； Thermal conductivity. ； Boron nitride ； Multi-walled carbon nanotube

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